Fireworks Leases 5MW of Blackwell Ultra Capacity at Era4's Chesterfield Site

Fireworks has contracted 5MW of direct-liquid-cooled capacity at Era4's data center in Chesterfield, Derbyshire. The deal, announced by the open-model AI company and the UK-based infrastructure provider, will run on Nvidia Blackwell Ultra HGX B300 GPUs (HGX B300 is Nvidia's high-density AI accelerator board). The capacity sits inside an HPE AI Mod POD modular data center, populated with HPE ProLiant Compute XD685 servers.

The agreement matters for two reasons. First, it pairs Fireworks' model training and inference platform with UK-owned and UK-operated infrastructure. Second, the initial target sectors are financial services, insurance, and life sciences. All three are regulated industries where data location carries legal weight.

What do the executives claim?

"Companies want AI they can specialize to their own data and the way they work," said Lin Qiao, co-founder and CEO of Fireworks. "They also want a choice about where those models run. This agreement with Era4 expands our capacity in the UK for developing new services for banks, fintechs, UK enterprises, and other regulated businesses."

The claim is broad. Fireworks already operates deployments in Germany and Iceland. The UK deal adds capacity, not a new capability category. What Fireworks has not disclosed: contract duration, pricing, or how many B300 GPUs 5MW actually buys.

Era4's CEO Tom Humphreys framed the deal as a sovereignty argument. "Europe has the talent, the data and the demand to lead in enterprise AI, but it cannot lead on compute it does not control," Humphreys said. "For a bank or insurer, knowing where its AI runs is part of the buying decision."

He added: "At Chesterfield, we own and operate the infrastructure, including behind-the-meter power generation. Working with Fireworks lets us build on that foundation with tools enterprises can use to adapt and run open models."

Behind-the-meter generation means power produced on site and consumed directly, without passing through the public grid first. That claim is verifiable in part. The Chesterfield site draws its primary power from landfill gas captured on site, with a grid connection held in reserve for backup. That is a concrete, checkable design choice rather than a marketing abstraction.

Who is Era4, and what does its track record show?

The company launched last year as Carbon3.ai and rebranded to Era4 earlier this year. In September 2025 it detailed its AI platform, claiming it would eventually comprise 100,000 GPUs across more than 30 locations. That target remains a claim, not a deployment. Chesterfield's 5MW lease is the company's first publicly contracted AI workload announcement with a named US platform partner.

The Derbyshire modular data center plans were unveiled in November 2025. In December, Era4 said it had signed an agreement to deploy Nvidia Blackwell Ultra AI infrastructure using HPE's direct liquid-cooled servers. The Fireworks contract extends that same hardware line into a live customer relationship.

Era4's site portfolio shows mixed results. A proposal for a site in Anglesey was rejected. The company has proposed another site in Canterbury, Kent, which would also be powered by landfill gas. It has also partnered with fellow UK company Civo to launch a sovereign AI cloud.

In late October, Era4 revealed it was targeting a 1GW AI campus in Newport, Wales. That would be by far its largest site. One gigawatt is roughly the continuous power demand of a small city, a scale that places the Newport plan far beyond anything Era4 has so far built or received planning approval for.

What remains unverified?

The announcement names capacity, hardware, and sectors. It does not name customers. No bank, insurer, or life sciences firm appears in the release as a signed user. The "initially target" phrasing signals intent, not revenue.

The 100,000-GPU and 30-location figures date from September 2025 and carry no timeline. The Newport 1GW figure is a target. The rejected Anglesey proposal shows the company's expansion plans face planning risk.

For regulated UK enterprises, the proposition is straightforward: open models (AI models with publicly available weights, which buyers can adapt to their own data) running on UK soil, with a named power source. Whether that proposition converts into signed enterprise workloads is the open question. The 5MW contract is real. Everything beyond it, so far, is announced intent.